ES2893798T3 - Device and method for printing width compensation - Google Patents

Abstract

Rotary printing machine (1) for printing a printing support web (2) guided in a web running direction LR through the rotary printing machine (1), the rotary printing machine (1) comprising a feeding device ( 3) for the printing support band (2), at least one printing unit (4) with a group of cylinders (5) which is in operative connection with the printing support band (2) during printing to print the printing support strip (2) on at least one side and at least one layout regulating device (6), the layout regulating device comprising at least one mechanical layout regulator (7), which can be put into operation. operative connection with the printing support band (2), and/or at least one layout regulator nozzle (7), characterized in that the at least one layout regulator device (6) is arranged, seen in the direction of web running LR, in front of the group of cylinders (5) of the, seen in the direction of web running LR, first printing unit (4-1), being able to, seen in the direction of web running, in front of the first unit of printing narrowing the printing support band at its effective width b.

Description

DESCRIPTION

Device and method for printing width compensation

The invention relates to a rotary printing machine for printing a printing support web guided through the rotary printing machine in a direction of web travel, the rotary printing machine comprising a feeding device for the printing support web, at least one printing unit with a group of cylinders, which during printing is in operative connection with the print carrier web, for printing the print carrier web on at least one side and at least one layout adjusting device .

Furthermore, the invention relates to a method for operating a rotary printing machine, in which a printing medium web with a web width B is fed to at least one printing unit in a direction of web travel by means of a feeding device and the printing support web being brought into operative connection with a group of cylinders of the at least one printing unit for printing at least one side, and the web width B of the printing support web is decreased to an effective width b by means of at least one arrangement regulator device.

Different problems with width variation are known from the state of the art, in particular with web-shaped printing media within the printing machine.

On rotary printing machines, in particular on web offset printing machines, on which paper webs are printed, usually four printing units are arranged one after the other for multicolor printing, seen in the direction of web travel. that with each printing unit a process ink can be applied to the print carrier web. In particular due to the action of the wetting agent in offset printing, the paper grows in particular transversely to the fiber direction, so that as the number of traversed printing units increases, the width of the printing medium increases. Since the printing arrangement applied with the first printing units increases in width with the printing medium, it is usual, due to this so-called fan-out effect, which is also highly dependent on the respective printing medium, to place, seen in the direction of web travel, behind the first printing unit so-called layout regulators, with which the print carrier web is undulated in front of the subsequent printing units and thus narrows in the projection towards the roller groove print to compensate for the flaring of previously applied print layouts and ensure a matched print of process inks.

DE 102004 004 264 C5 discloses, for example, such a printing machine equipped with layout regulators, as well as a method for compensating for the increase in width of the print medium web.

DE 199 18399 A1 teaches a rotary printing machine, in which a varying web width due to tensile stresses between the printing units is compensated by using an additional pulling device in front of the first printing unit, a corresponding web tension is already established in the area in front of the first printing unit.

DE 102015 112780 A1 discloses a rotary printing machine, in which the web width that increases due to moisture absorption is compensated by arrangement regulators arranged behind the first printing unit, the fan compensation operation being performed. -out automatically by detecting printed markings.

A completely different problem with varying the print media width results when printing relatively elastic substrates, such as web-shaped plastic film printing. In packaging printing machines, web-shaped plastic film is unwound from reels by a feeding device, such as a reel changer or unwinder, and fed with or without a separate means for establishing a tension. to at least one printing mechanism, in which the print medium is held between a pair of printing cylinders and printed during rotation of the printing cylinders. Printing units of this type with printing cylinders that are mechanically in contact with the printing medium are used, for example, in the process of offset printing, flexographic printing or gravure printing.

Usually, the printing medium is printed with several printing units arranged one behind the other, so that the web of printing medium is held and transported by several groups of cylinders to print it.

However, this firm holding of the print substrate web within the printing units has the consequence on elastic substrates of this kind, such as plastic films, that the print medium behind the cylinder group of the printing When viewed in the direction of web travel, the first printing unit is extended or stretched in the longitudinal direction and thus in the direction of web travel, so that the width of the print medium decreases as a result. Since print media of this type also do not absorb humidity, on the other hand, growth of the printing medium does not take place either. The print layout that is applied with the first print unit is therefore still applied on the original web width media B, while the print layouts that are applied with the subsequent print units are applied on a printing support web with decreased width. The result of this is that the print layout applied by the first printing unit is narrower than the print layouts applied by the subsequent printing units, resulting in problems with the registration, respectively the registration, of the different inks. of printing, respectively of process with each other.

It is known from practice as a solution to this problem that in the previous step the width of the first print arrangement is scaled correspondingly, in this case there are no correction possibilities within the machine, so that consequently no response can be made. to different behaviors of different media, cylinder covers, etc. As a consequence, deviations in the registration, respectively registration, in particular of the applied first printing ink, respectively process ink, can occur.

The invention is therefore based on the object of creating a solution, with which the variation in the width of the first printing arrangement can be compensated.

The object is achieved by means of a device according to claim 1 and a method according to claim 3. The device according to the invention comprises a rotary printing machine, in which at least one arrangement regulator device comprises at least one regulator viewable, which can be brought into operative connection with the print carrier web, and/or at least one layout regulator nozzle is arranged, seen in the direction of web travel LR, in front of the cylinder group of the, seen in direction of travel of band LR, first printing unit.

The method according to the invention relates to a method for operating a rotary printing machine, in which the reduction of the web width B to an effective width b is carried out, seen in the direction of web travel, in front of the group of printing cylinders. la, seen in the direction of web travel, first printing unit.

Such a device, as well as such a method, has the advantage that it is possible to react directly in the printing machine to the respective specific elongation of the print medium and the resulting narrowing and thus to the reduction. width of the printing support web, without having to perform scaling of the first printing mold, so that a print containing registration, respectively registration, of the respective process inks with each other is ensured.

In an advantageous configuration, not only is a layout adjusting device arranged in front of the first printing unit, seen in the direction of web travel, but in addition to this layout adjusting device also in front of the roller group of at least one printing unit which, seen in the direction of web travel, is subsequent to the first printing unit, an arrangement regulator is arranged, also seen in the direction of web travel, downstream of the arranged printing unit. Accordingly, changing web tension conditions within the printing unit array, for example resulting from different printing methods, can be reacted to and the effective web width B within the printing unit array adapted.

Preferred further developments of the invention result from the subclaims and the following description. Different manufacturing examples of the invention will be explained in detail, without being limited to this, on the basis of the drawings. In this they show:

FIG. 1 shows the variation of the web width B in the first printing unit, seen in the direction of web travel, in rotary printing machines known from the state of the art

FIG. 2 a schematic representation of a rotary printing machine according to the invention

FIG. 3 a schematic view from above of the print carrier web in front of and behind the first printing unit in a rotary printing machine according to the invention, seen in the direction of web travel

FIG. 4 a schematic representation of an advantageous configuration of a rotary printing machine according to the invention

FIG. 5 shows a first manufacturing variant for corrugating the printing support web

FIG. 6 shows a second production variant for corrugating the printing support web

FIG. 1 shows a view from above of the printing support web 2 in the region of a rotary printing machine 1 known from the state of the art, in which the printing support web 2 is in operative connection. with a group of cylinders 5 and is printed on at least one side with a printing or process ink by at least one of the impression cylinders of the group of cylinders 5.

Printing machines of this type are, for example, the offset, gravure and flexographic printing machines known from the state of the art. In the case of an offset printing machine, the group of cylinders 5 consists of either a plate cylinder for holding the impression mold, a transfer cylinder, which is covered with a printing blanket, and a counter pressure cylinder or in each case of a pair of plate holder and transfer cylinders in each case on the upper band and lower band sides. The printing support web 2 is therefore held by the groups of cylinders 5 of the printing units which are usually in plurality and arranged one behind the other in the direction of web travel LR, and transported by the rotation of the rollers. impression cylinders, whereby a corresponding web tension is established. Also behind the at least one printing unit 4 is usually arranged at least one component for conveying the web, so that the effect described below is ascertained also in such a case.

Due to the clamping of the print carrier web 2 by means of the roller group 5 of the at least one printing unit 4, different web tensions over the entire length of the print carrier web 2 can no longer be compensated. which the printing machine 1 is located, so that due to the usually higher web tension produced from the first printing unit 4, in particular on print media with a relatively low modulus of elasticity, such as, for example, on plastic films, an elongation or stretching of the print carrier web 2 in the longitudinal direction and thus in the direction of the web running direction LR, so that as a consequence of the volume of the print carrier web 2 that remains constant it narrows, so that the original bandwidth B is reduced to an effective width b.

Figure 1 shows this effect, which is known in rotary printing machines 1 known from the state of the art, in the form of a view perpendicular to the plane defined by the printing support band 2 in the area in front and behind, seen in web direction of travel LR, first printing unit 4-1.

The print media web 2 is fed in this case in the web running direction LR to the first printing unit 4-1 and runs through it, the print media web 2 being in operative connection with the print media group. cylinders 5, which is not shown in Fig. 1, of the first printing unit 4-1 and thereby printing it with a first printing or process ink. Consequently, seen in the direction of web travel LR, the print carrier web 2 is printed on at least one side, which is schematically represented in FIG. 1 by text fields and a graphic.

The print media web 2 is fed into the first printing unit 4-1 with the original web width B and, due to the clamping point inside the first printing unit 4-1 and the usually higher web tension Starting from the first printing unit 4-1, the printing medium web 2 narrows, so that behind the first printing unit 4-1 the printing medium web 2 has a reduced effective width b compared to with the original bandwidth B. The decrease in the B-band width is usually in the range of a few thousand to low percent values, relative to the B-band width, which is, however, sufficient to visually affect the print layout.

If this print medium web 2 is fed with a print medium web 2, which has a decreased effective width b compared to the original web width B, to a subsequent printing unit 4-2 not shown in the figure 1, deviations in registration, respectively registration, occur if the printing forms of the first printing unit 4-1 and the second printing unit 4-2 have the same width.

Figure 2 shows a rotary printing machine 1 according to the invention, with which the phenomenon shown in Figure 1 is eliminated.

The rotary printing machine 1 shown by way of example in FIG. 2 is essentially a rotary printing machine 1 as is essentially known from the prior art and is used to print a print carrier web 2 guided in a direction of travel. LR web through rotary printing machine 1.

The print carrier web 2 is fed to the printing units 4 by means of a feed device 3 and as feed device 3 usually reel changers or unwinders are used, in which the print carrier web 2 is unwound from one coil. In most cases, but not necessarily, the feed device 3 comprises elements for laterally aligning the print carrier web 2 and/or for establishing a defined web tension, such as, for example, a feed mechanism .

The print carrier web 2 is fed in the web running direction LR to a plurality of printing units 4, which, seen in the web running direction LR, are arranged one behind the other. In the example shown in FIG. 2, four printing units 4 are arranged one behind the other, but the number of printing units 4 can be correspondingly larger or smaller. Each printing unit 4 comprises a group of cylinders 5 which in the example shown in figure 2 is made up of a plate-holding cylinder and a transfer cylinder on the upper side of the band, and a counter-pressure cylinder on the lower side of the band. The configuration of the group of cylinders 5 can also be configured differently from the example shown in figure 2, for example for two-sided offset printing, for gravure printing or, for example, with a central cylinder and plate cylinders. and of transfer arranged around in satellite form, as it is known from flexographic printing.

The print medium web 2 is held by each cylinder group 5, since a corresponding compression must prevail for the transfer of the printing or process ink to the print medium.

Although a horizontal web-guided rotary printing machine is shown as an example in Figure 2, the present invention can also be applied to any other configuration of a rotary printing machine 1, for example, a web-guided rotary printing machine 1. vertical band, on which the printing units 4 are superimposed.

The rotary printing machine 1 according to the invention shown in Figure 2 further comprises a layout regulator device 6 comprising a plurality of layout regulators 7 arranged side by side and generally distributed over the web width B.

These shims 7 can be configured as rotatably supported roller-shaped mechanical shims 7 which come into contact with the print carrier web 2 in the mould, so that the print carrier web 2 undulates. .

However, the layout regulators 7 can alternatively also be configured as nozzles charged with compressed air and thus as layout regulator nozzles 7, so that there is no longer any mechanical contact between the print carrier web 2 and each layout regulator 7, since an air cushion is established between each layout regulator 7 and the printing medium web 2.

In the rotary printing machine 1 according to the invention shown in FIG. 2, the layout adjustment device 6 is arranged, seen in the direction of web travel LR, in front of the group of cylinders 5 of the, seen in the direction of web travel LR , first printing unit 4-1, so that the print substrate web 2 is corrugated already in front of the first cylinder group 5 and thus in front of the first cylinder group 5 by means of an arrangement adjusting device 6 and thus it narrows in its effective width b. Although it is not shown in Figure 2, it is also possible to arrange in front of the group of cylinders 5 of the first printing unit 4-1 a plurality of arrangement regulating devices 6, in the direction of travel LR or perpendicular to it, for the waviness of the printing support web 2.

In the representation shown in FIG. 2, the layout adjustment device 6 is arranged in front of the first printing unit 4-1, seen in the direction of web travel LR. Although it is not shown in FIG. 2, it is also possible to arrange the layout adjustment device 6 relatively just in front of the cylinder group 5 of the first printing unit 4-1 and thus, seen spatially, already within the contour of the first 4-1 printing unit.

Fig. 3 represents a view from above on the printing support web 2 in the area around the first printing unit 4-1 and shows the effect of the method executed with the rotary printing machine 1 according to the invention.

The basic arrangement of the cutout, which is shown in FIG. 3, of the print carrier web 2 in the area in front of and behind the first printing unit 4-1 is identical to the cutout shown in FIG. 1, but with the result of the method according to the invention, so that a repetition of the area of rotary printing machine 1 shown there is dispensed with here.

However, Fig. 3 shows the layout adjuster device 6, which in this view is covered by the print carrier web 2 and is therefore shown in dashed lines, with the corresponding five layout adjusters 7 shown as dots. example, which, seen in the web running direction LR, is arranged in front of the roller group 5, which is not shown in FIG. 3, of the first printing unit 4-1, seen in the web running direction LR .

As already mentioned under FIG. 2, it makes no difference whether the layout adjustment device 6 is arranged in front of the first printing unit 4-1 or within the contour of the first printing unit 4-1, but, seen in web direction of travel LR, in front of the cylinder group 5 of the first printing unit 4-1, since this essentially depends on the contour of the printing unit 4 and the geometric arrangement of the cylinder group 5 within the unit 4. The determining criterion is that the layout adjusting device 6 is arranged in front of the cylinder group 5 of the first printing unit 4-1 and thus in the region of the print carrier web 2 not yet printed.

As schematically represented in Fig. 3, the printing medium web 2, which is fed by the feeding device 3, with the web width B is corrugated in front of the cylinder group 5 of the first printing unit 4-1 by a layout adjusting device 6. The effective width b projected onto the plane defined by the print media web 2 is therefore less than the original web width B, so that in top view and hence Consequently, in the projected plane the not-yet-printed print support web 2 narrows. The deflection and thus the waviness of the printing medium web 2 can be adjusted by adjusting the layout adjusters 7 of the layout adjusting device 6 such that preferably the effective width b in front of the cylinder group 5 of the first printing unit 4-1 is identical to the effective width b behind the printing unit 4-1, so that the printing arrangements which are all applied on a web of printing medium 2 with identical effective width b by means of printing units, which are usually in a plurality and are arranged one behind the other, and thus do not exhibit registration or registration deviations of the respective process inks from each other.

Since the narrowing of the printing medium web 2 is usually in the range of per thousand of the web width B, at most in the low range of percent of the web width B, there does not occur, therefore, analogous to the known state of the art, no creasing when the print carrier web 2 runs through the roller group 5.

Figure 4 shows an advantageous configuration of a rotary printing machine 1, in which the at least one layout adjusting device 6 is arranged, in addition to the, seen in the direction of web travel LR, the first printing unit 4- 1 also in front of the group of cylinders 5 of at least one printing unit 4 which, seen in the direction of web travel LR, is arranged downstream of the first printing unit 4-1.

In the example shown in Fig. 4, a layout adjusting device 6 is arranged in front of the cylinder group 5 of the first printing unit 4-1 and, in addition, an arrangement adjusting device 6 is arranged in front of the cylinder group 5 of the third printing unit 4-3. This is a purely exemplary production, since an arrangement adjusting device 6 can additionally be arranged in front of the cylinder group 5 of the first printing unit 4-1 also in front of the cylinder group 5 of the second printing unit 4-2 and/or in front of cylinder group 5 of the third printing unit 4-3 and/or in front of cylinder group 5 of the fourth printing unit 4-4 and, if necessary, other printing units 4 subsequent not represented in the drawing.

With such a configuration of the rotary printing machine 1, respectively of the method carried out therewith, it is possible to change and adjust the effective width b also within the set of printing units 4, for example, when using settings of different printing and/or different printing procedures.

Fig. 5 shows a schematic view of the layout adjusting device 6 in the direction of web travel LR in a configuration, in which a layout adjusting device 6 is arranged on the underside of the printing medium web 2 and the web of printing medium 2 is therefore corrugated in the shape of an arc segment. In this manufacture, in order to decrease the original web width B to an effective web width b, the recording medium web 2 is flexed, relative to the plane defined by the recording medium web 2, in one direction.

In the variant shown in Figure 5, the layout regulator device 6 has, for example, five layout regulators 7, the number of layout regulators 7 not generally being decisive and this being able to vary between two and ten in practice. , which essentially depends on the bandwidth B and the print medium.

Figure 6 shows a schematic view in direction of travel of web LR comparable to figure 5 in another configuration, in which print carrier web 2 is corrugated by in each case an arrangement adjusting device 6 on the upper side and the underside of the printing support web 2. In this fabrication, to decrease the original web width B to an effective web width b, the printing support web 2 is flexed, relative to the plane defined by the print support band 2, in both directions.

In the variant shown in FIG. 6, the upper layout regulator device 6 has, for example, two layout regulators 7 and the lower layout regulator device 6 has three layout regulators 7, the number of which is generally not decisive. layout regulators 7 and this can vary between two and ten in practice, which essentially depends on the width of the band B and the printing medium.

Reference character list

1 rotary printing machine

2 Printing support band

3 feeding device

4 Printing unit

cylinder group

Disposition regulator device

Disposal Regulator / Disposal Regulator Nozzle

LR Belt running direction

B Bandwidth

b Effective width

Claims (6)

1. Rotary printing machine (1) for printing a printing medium web (2) guided in a web running direction LR through the rotary printing machine (1), the rotary printing machine (1) comprising a feed (3) for the printing support web (2), at least one printing unit (4) with a group of cylinders (5) that is in operative connection with the printing support web (2) during printing printing to print the printing support web (2) on at least one side and at least one layout regulator device (6), the layout regulator device comprising at least one mechanical layout regulator (7), which can be brought into operative connection with the printing support web (2), and/or at least one layout regulator nozzle (7), characterized in that the at least one layout regulator device (6) is arranged, seen in direction of movement of band LR, in front of the group of cylinders (5) of the first printing unit (4-1), seen in the direction of the web LR, with which, seen in the direction of web travel, in front of the first printing unit, the support web can be narrowed printing in its effective width b. 2. Rotary printing machine according to claim 1, characterized in that the at least one layout adjustment device (6) is arranged, in addition to the first printing unit (4-1) seen in the direction of web travel LR. , also in front of the group of cylinders (5) of at least one printing unit (4) which, seen in the direction of web travel LR, is arranged downstream of the first printing unit (4-1). 3. Method for operating a rotary printing machine (1), a printing support web (2) with a web width B being fed by means of a feeding device (3) to at least one printing unit (4) in a band running direction LR, and putting, to print the printing support band (2) at least on one side, that in operative connection with a group of cylinders (5) of the at least one printing unit (4 ), and the web width B of the printing support web (2) narrows, due to the increased web tension, seen in web running direction LR, behind the group of cylinders (5) of the first unit of printing (4-1), to an effective web width b, characterized in that to compensate for the narrowing of the printing support web (2) due to web tension that narrows, seen in the direction of web travel LR, in front of the first printing unit (4-1) to the effective web by means of regulators d and disposition (7). Method according to claim 3, characterized in that the reduction of the width of the band B to an effective width b is carried out, seen in the direction of movement of the band, in front of the group of rollers (5) of the, seen in the direction of movement of web LR, first printing unit (4-1) and at least, seen in the direction of travel of the web, in front of the group of cylinders (5) of a printing unit (4) which, seen in the direction of travel of band LR, is disposed downstream of the first printing unit (4-1). Method according to one of claims 3 to 4, characterized in that in order to decrease the web width B to an effective width b, the print support web (2) is flexed, relative to the plane defined by the printing support web. printing (2), only in one direction. Method according to one of claims 3 to 4, characterized in that in order to decrease the web width B to an effective width b, the print support web (2) is flexed, relative to the plane defined by the printing support web. printing (2), in both directions.